- Volume 3, Issue 4, 2017
Volume 3, Issue 4, 2017
- Research Article
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- Responses to Human Interventions
- Antibiotics
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A population genomics approach to exploiting the accessory 'resistome' of Escherichia coli
More LessThe emergence of antibiotic resistance is a defining challenge, and Escherichia coli is recognized as one of the leading species resistant to the antimicrobials used in human or veterinary medicine. Here, we analyse the distribution of 2172 antimicrobial-resistance (AMR) genes in 4022 E. coli to provide a population-level view of resistance in this species. By separating the resistance determinants into ‘core’ (those found in all strains) and ‘accessory’ (those variably present) determinants, we have found that, surprisingly, almost half of all E. coli do not encode any accessory resistance determinants. However, those strains that do encode accessory resistance are significantly more likely to be resistant to multiple antibiotic classes than would be expected by chance. Furthermore, by studying the available date of isolation for the E. coli genomes, we have visualized an expanding, highly interconnected network that describes how resistances to antimicrobials have co-associated within genomes over time. These data can be exploited to reveal antimicrobial combinations that are less likely to be found together, and so if used in combination may present an increased chance of suppressing the growth of bacteria and reduce the rate at which resistance factors are spread. Our study provides a complex picture of AMR in the E. coli population. Although the incidence of resistance to all studied antibiotic classes has increased dramatically over time, there exist combinations of antibiotics that could, in theory, attack the entirety of E. coli, effectively removing the possibility that discrete AMR genes will increase in frequency in the population.
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Diversity, virulence, and antimicrobial resistance of the KPC-producing Klebsiella pneumoniae ST307 clone
The global spread of Klebsiella pneumoniae producing Klebsiella pneumoniae carbapenemase (KPC) has been mainly associated with the dissemination of high-risk clones. In the last decade, hospital outbreaks involving KPC-producing K. pneumoniae have been predominantly attributed to isolates belonging to clonal group (CG) 258. However, results of recent epidemiological analysis indicate that KPC-producing sequence type (ST) 307, is emerging in different parts of the world and is a candidate to become a prevalent high-risk clone in the near future. Here we show that the ST307 genome encodes genetic features that may provide an advantage in adaptation to the hospital environment and the human host. Sequence analysis revealed novel plasmid-located virulence factors, including a cluster for glycogen synthesis. Glycogen production is considered to be one of the possible adaptive responses to long-term survival and growth in environments outside the host. Chromosomally-encoded virulence traits in the clone comprised fimbriae, an integrative conjugative element carrying the yersiniabactin siderophore, and two different capsular loci. Compared with the ST258 clone, capsulated ST307 isolates showed higher resistance to complement-mediated killing. The acquired genetic features identified in the genome of this new emerging clone may contribute to increased persistence of ST307 in the hospital environment and shed light on its potential epidemiological success.
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- Review
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- Microbe-Niche Interactions
- Pathogenesis
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Human genome-microbiome interaction: metagenomics frontiers for the aetiopathology of autoimmune diseases
More LessA short while ago, the human genome and microbiome were analysed simultaneously for the first time as a multi-omic approach. The analyses of heterogeneous population cohorts showed that microbiome components were associated with human genome variations. In-depth analysis of these results reveals that the majority of those relationships are between immune pathways and autoimmune disease-associated microbiome components. Thus, it can be hypothesized that autoimmunity may be associated with homeostatic disequilibrium of the human-microbiome interactome. Further analysis of human genome–human microbiome relationships in disease contexts with tailored systems biology approaches may yield insights into disease pathogenesis and prognosis.
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